Hide ads when reading articles in Safari on Mac
You can use Safari Reader to view a web page article in one page, formatted for easy reading, and presented without ads, navigation or other distracting items. You can adjust font, font size and background colour for Reader.
View an article using Reader
In the Safari app
on your Mac, click the Reader button 
at the left end of the Smart Search field.The button appears only if the web page has an article that Reader can show.
To stop using Reader, click the Reader button again or press Esc.
Change how your web pages look in Reader
In the Safari app
on your Mac, while viewing an article in Reader view, click the letter button 
that appears at the right end of the Smart Search field.Do any of the following to adjust the settings:
Choose a font size.
Choose a white, sepia, grey or black background.
Choose a font.
Reader always shows you the last font, size and background you chose.